Raman Scattering in Zn_1-xMg_xSe Mixed Crystals

Abstract

This paper presents results of investigations of the Raman scattering of vibrational modes in Ζn1-xMgxSe crystals for the range of composition 0 < x < 0.43. The Raman polarized spectra of Zn1-x Mgx Se were measured at room temperature. The typical Raman spectrum shows four peaks which can be interpreted as longitudinal and transverse optical ZnSe-like and MgSe-like phonons. The ZnSe-like and MgSe-like vibrations can be described by the modified random element isodisylacement model. Results of the Raman measurements in the investigated range of composition confirm the two-mode behaviour of the optical phonons in the mixed Zn1-x MgxSe crystals.PACS numbers: 78.30. Fs, 78.55.Et, The physical properties of wide gap II-VI ternary and quaternary mixed crystals have been recently extensively studied. The current interest in these materials arises from scientiflc and application points of view. As far as an application is concerned, ternary and quateuary II-VI alloys are especially interesting in the context of possibility of an additional control of band gap energies, lattice constants as well as conduction and valence bands offsets in heterostructures. These parameters are very important for effective carriers injection and radiative recombination processes in electroluminescent devices based on multilayer heterostructures.For the study of vibrational properties of mixed crystals the Raman scattering is widely used as the experimental method. The vibrational spectra of tetrahedrally coordinated semiconduction where a fraction of cations is replaced by an

Vibrational spectroscopy of compound semiconductor nanocrystals

“…With approaching the end-point crystals (x → 0 or x → 1), the LO and TO phonon frequencies of the minority anion or cation sublattice tend to adopt the local vibration frequency of the corresponding impurity. The experimental data show the two-mode behaviour to be characteristic for CdS 1−x Se x [302,303], CdSe 1−x Te x [304][305][306], CdS 1−x Te x [307], ZnS 1−x Se x [308,309], ZnS 1−x Te x [310], Cd 1−x Mn x Se [299,311], Zn 1−x Mg x Se [312], Cd 1−x Zn x Te [313,314], Cd 1−x Mg x Te [315], Cd 1−x Mn x Te [315], Zn 1−x Mg x Te [21], and Cd 1−x Hg x Te [316] ternary II-VI systems. Note that for Cd 1−x Hg x Te, as shown by a recent study [316], the low-temperature lattice dynamics is somewhat more complicated; the same applies for Cd 1−x Zn x Te, where a fine structure in the far-infrared spectrum was reported [317].…”